When collecting metals or resins from waste such as a used electronic product including the metals or resins as the builders, typically, various separating processes are performed on a mixture of different types of substances obtained by grinding the waste or part thereof. For example, Patent Document 1 (JP 2010-524663A discloses a recycling method, including a process that places shredder residue obtained from waste into a sink-float tank, and separates the residue into metal residue and plastic residue using the difference in density or specific gravity, a process that separates, by type, the metal residue using an air separator, a magnetic belt, or the like, and a process that separates, by type, the plastic residue using a temperature separator, a hydrocyclone, or the like.
The method disclosed in Patent Document 1 employs a plurality of separators, tanks, and the like in order to realize the above-described separating processes, and thus, a complicated and large-scale system is necessary for realizing this method. Meanwhile, Patent Document 2 (JP 2002-59026A) discloses a method for sorting a mixture using the magneto-Archimedes effect. According to this method, a mixture of a plurality of types of diamagnetic plastic particles is placed into a supporting liquid, and a magnetic field having a magnetic field gradient, that is, a gradient magnetic field is applied thereto, so that the diamagnetic plastic particles in the mixture float at positions corresponding to their physical properties (volume susceptibility and density), and the plastic particles are sorted by type. If a mixture containing a plurality of types of substances, such as a mixture obtained from waste as disclosed in Patent Document 1, is separated by type using the magneto-Archimedes effect (or magnetic force or magnetic buoyancy applied to particles in a medium) as in the invention described in Patent Document 2, the separating apparatus and the separating process will be significantly simplified and more efficient.